Gday, Just a question here.. Purchased my magna off a mate that had it around 5 years, he ALWAYS bought ethanol fuel. The accelerator pedal has been getting more & more sticky each month, having to really crack on it when you first get in the car to UNstick it.. ended up being carbon buildup around the butterfly in the Throttle body.

Im wondering if the ethanol fuel thats been used in this car for 5+ years straight would have caused this buildup of soot in my TB or if it would have happened regardless of what fuel he had been using ?

No fuel goes through the throttle body - it is injected near the intake valves. So don't blame the fuel, or your mate. Crank case fumes from the rocker cover do though, and that can leave an oily carbon mess in the throttle body and intake ducting near the throttle body. Clean it out, and check that the throttle stop screw is set right, it should just hold the butterfly open slightly to prevent binding. It can start binding after many years as the throttle shaft wears. Give it a slight turn in, like one eight of a turn,and test the throttle for stickiness. So, its not fuel but general wear and tear on the engine that causes the carbon build up and binding.

The oily carbon build up gets worse as the mileage accumulates, so it might be worthwhile checking the build up regularly. How many Km on the engine, and does it use oil?

Actually completely the oppisite! Ethanol is a cleaner burning fuel then petrol is!

The problem with E10 is, "91 E10" doesnt actually start out as 91, 91 is the rating of the fuel AFTER the ethanol is added as it bumps up the octane rating. It should not cause any extra buildup.

Anyways, back on topic. What kind of oil has been used in it, and was there an oily build-up in intake hose connected to the throttle body? maybe a catch can is the way to go! :)

http://wiki.answers.com/Q/What_is_an_oil_catch_can

Actually completely the oppisite! Ethanol is a cleaner burning fuel then petrol is!


Doesn't make a difference - no fuel goes through the throttle body! lol

But a catch can, or some sort of filter on the breather is a good idea.

kk, yup i have cleaned it out & its ok now, I realise its only air intake but before you guys telling me that its oil, I wasnt sure if it didnt somehow end up with fuel vapors or something heading back up toward the butterfly, just want sure, was bugging me!..

230,000k.. looks nice and clean inside the rocker covers, unsure what oil he was using im about to do a oil change this week, didnt notice any oil buildup in any of the hoses, i had a peep down all of them as I put the plenum chamber back on yesterday after changing valve cover gaskets & plug seals. PCV gave a rattle when i shook it so I think thats ok & scum free.

There is a carbon canister on the car that soaks up vapours from the fuel tank when the car is parked, but I believe it is only vented back into the intake when the engine is on. Where this vapour enters the intake I don't know. Perhaps find and check the check valve on the cannister? Sits on top and has a vacuum hose attached IIRC.

yep i think i know the canister you speak of, i will check it today.. at least my driveways clean today !!.. no massive oil pools everywhere lol